rear bumper and spare tire carrier

Big Blue, my '85 F250HD, is in need of a place to put the spare tire instead of in the bed taking up room.  And, since the tires are big and I'm going with a 38 gallon rear tank, under the truck isn't an option.

I've done some looking but haven't found what I want, so I'm drawing it up and am planning to have it built to spec.  These pics will change over time as I fine tune the plans, but I wanted some place to put them, so here are some pics.